1. Field of the Invention
The present invention relates to a corneal surgical apparatus for incising the cornea of an eye of a patient in a layered form at the time of a keratorefractive surgery or the like.
2. Description of the Related Art
In recent years, attention has been focused on LASIK (laser in situ keratomileusis) surgery for effecting keratorefractive treatment wherein after a flap is formed by incising a corneal portion with a thickness of 150 xcexcm ranging from the corneal epithelium to the corneal stroma with one end of the cornea remaining connected like a hinge, the corneal stroma is cut away or ablated in a refractive correction amount by excimer laser light, and the flap is then returned to its original position. In this LASIK surgery, a corneal surgical apparatus called a microkeratome is used to incise the cornea in a layered form.
Such microkeratome is available that has a suction ring vacuum-fixed to a portion of the cornea ranging from a corneal ring portion to the surface of the conjunctiva, a cornea applanating member for applanating the cornea flatly, and a blade which, while being oscillated in the lateral direction, is linearly moved or rotatively moved in a direction toward the hinge along a guide mechanism provided on the suction ring, so as to incise the cornea into a layered form with a substantially uniform thickness.
The guide mechanism is arranged such that a rack is provided on the suction ring, while a rotating gear meshing with the rack is provided on the blade side so that the blade is moved while being guided by the rack as the rotating gear is rotated. Another known guide mechanism is arranged such that the blade is moved along a guide groove provided on the suction ring.
In addition, the following mechanisms are also known: one in which the lateral oscillation of the blade and the movement of the blade toward the hinge are effected by a single motor provided in an apparatus body; one in which rotatively driving forces of two motors in a controller provided separately from the apparatus body are respectively transmitted to a blade oscillating mechanism and a blade moving mechanism in the apparatus body through two wires, so as to separately control the oscillation and movement of the blade; and one in which the oscillation speed and the translation speed of the blade can be variably set, respectively.
However, as for the microkeratome which has a guide mechanism or a gear mechanism on the suction ring, there are cases where the patient""s eyelashes bite into the guide mechanism during a surgical operation to stop the movement of the blade. In this case, it is necessary to resume the operation after removing the eyelashes, but this imposes an adverse effect on the patient""s eye. Further, a layered incision with an equal thickness cannot be realized by the re-operation. Since the guide mechanism causes abrasion dust, there is apossibility that the abrasion dust enters into the patient""s eye if the guide mechanism is provided on the suction ring.
The characteristics of the cornea and the intraocular pressure differ depending on the patient""s eye, but in the case of the microkeratome in which the lateral oscillation and movement of the blade are effected by one motor, it is difficult to optimize the relationship between the feeding movement and the lateral oscillation for obtaining a satisfactorily smooth surface as the incised surface.
In the case of the microkeratome in which the rotatively driving forces of two motors in a controller are transmitted to the blade oscillating mechanism and the blade moving mechanism through the two wires, the wires hinder the surgical operation.
In addition, unless the relationship between the set oscillation speed and the set translation speed of the blade is appropriate, the following problems can possibly occur. If the translation speed is excessively faster than the oscillation speed (the oscillation speed is excessively slower than the translation speed), the cut surface of the cornea may become nonuniform. On the other hand, if the translation speed is excessively,slower than the oscillation speed (the oscillation speed is excessively faster than the translation speed), frictional heat may occur on the cut surface, or extra time is needed until the incision is completed, so that the efficiency is poor.
In view of the above-described problems, it is an object of the present invention to provide a corneal surgical apparatus which eliminates the possibility of an interruption of surgery caused in connection with a guide mechanism and which permits a satisfactory surgical operation appropriate to the condition of the patient""s eye without imposing an adverse effect on the patient""s eye.
Another object of the present invention is to provide a corneal surgical apparatus which makes it possible to perform the incision of the cornea efficiently and satisfactorily by appropriately setting the oscillation speed and the translation speed of the blade.
To overcome the above-desciribed objects, the present invention is characterized by the following features.
(1) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form using a blade, includes:
a blade moving shaft supported rotatably and axially movably, wherein axial movement of the blade moving shaft causes the blade to advance or retract and rotation of the shaft causes the blade to make lateral oscillation;
first driving means, having a first motor, for axially moving the blade moving shaft by rotation of the first motor; and
second driving means, having a second motor, for rotating the blade moving shaft by rotation of the second motor.
(2) The corneal surgical apparatus according to (1), wherein the first driving means includes:
a feed screw portion which is rotated by the rotation of the first motor; and
a connecting member meshing with the feed screw portion and rotatably holding the blade moving shaft.
(3) The corneal surgical apparatus according to (1), wherein the second driving means includes:
a rotation transmitting member for holding the blade moving shaft axially slidably, and rotating the blade moving shaft by the rotation of the second motor.
(4) The corneal surgical apparatus according to (3), wherein the blade moving shaft includes a spline shaft having a first portion circular in section and a second portion noncircular in section, and the second portion is slidable with respect to the rotation transmitting member.
(5) The corneal surgical apparatus according to (1), further includes:
controlling means for controlling the first driving means so as to cause the blade to advance or retract at a predetermined moving speed, and controlling the second driving means so as to oscillate the blade at a predetermined oscillation speed.
(6) The corneal surgical apparatus according to (5), further includes:
setting means for variably setting at least one of the moving speed and the oscillation speed.
(7) The corneal surgical apparatus according to (6), further includes:
determining means for determining whether or not a relationship between the moving speed and the oscillation speed is appropriate.
(8) The corneal surgical apparatus according to (7), further includes:
storing means for storing a relative allowable setting range of the moving speed and the oscillation speed,
wherein the determining means determines whether or not the relationship between the moving speed and the oscillation speed is appropriate on the basis of the allowable setting range stored in the storing means.
(9) The corneal surgical apparatus according to (1), further includes;
setting means for variably setting two parameters which respectively correspond to a moving speed of the blade defined by the first driving means and an oscillation speed of the blade defined by the second driving means;
storing means for storing a relative allowable setting range of the moving speed and the oscillation speed;
limiting means for limiting the allowable setting range of one of the parameters on the basis of both the allowable setting range stored in the storing means and the other of the parameters set by the setting means; and
controlling means for controlling the first driving means and the second driving means on the basis of the parameters set by the setting means.
(10) The corneal surgical apparatus according to (1), further includes:
first setting means for variably setting one of two parameters which respectively correspond to a moving speed of the blade defined by the first driving means and an oscillation speed of the blade defined by the second driving means;
storing means for storing an optimum combination of the moving speed and the oscillation speed;
second setting means for setting the other of the parameters on the basis of both the combination stored in the storing means and the one of the parameters set by the first setting means; and,
controlling means for controlling the first driving means and the second driving means on the basis of the parameters set by the first setting means and the second setting means.
(11) The corneal surgical apparatus according to (1), further includes:
position detecting means for detecting a position of the blade; and
controlling means for controlling at least one of a moving speed of the blade defined by the first driving means and an oscillation speed of the blade defined by the second driving means on the basis of position information obtained by the position detecting means.
(12) The corneal surgical apparatus according to (1), further includes:
changeover means for changing over at least one of a moving speed of the blade defined by the first driving means and an oscillation speed of the blade defined by the second driving means in association with how degree a surgical operation proceeds.
(13) The corneal surgical apparatus according to (1), further includes:
a suction ring for abutment against the partient""s eye;
sucking means for sucking air in a gap formed between the suction ring and the patient""s eye to fix the suction ring onto the patient""s eye;
pressure detecting means for detecting air pressure in the gap which varies due to the suction by the sucking means; and
controlling means for controlling at least one of the first driving means and the second driving means on the basis of pressure information detected by the pressure detecting means.
(14) The corneal surgical apparatus according to (13), further includes:
suction controlling means for controlling the sucking means on the basis of the pressure information detected by the pressure detecting means.
(15) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form using a blade, includes:
oscillating means for laterally oscillating the blade;
moving means for moving the blade in an incising direction;
setting means for variably setting at least one of a moving speed and a oscillation speed of the blade; and
determining means for determining whether or not a relationship between the moving speed and the oscillation speed is appropriate.
(16) The corneal surgical apparatus according to (15) further includes:
notifying means for notifying an operator of a result of determination by the determining means.
(17) The corneal surgical apparatus according to (15), further includes:
controlling means for controlling the oscillating means and the moving means on the basis of a result of determination by the determining means.
(18) The corneal surgical apparatus according to (15), further includes:
storing means for storing a relative allowable setting range of the oscillation speed and the moving speed,
wherein the determining means determines whether or not the relationship between the oscillation speed and the moving speed is appropriate on the basis of the allowable setting range stored in the storing means.
(19) The corneal surgical apparatus according to (18), further includes:
displaying means for displaying the allowable setting range when it is determined by the determining means that the relationship between the oscillation speed and the moving speed is inappropriate.
(20) The corneal surgical apparatus according to (18), further includes:
resetting means for resetting at least one of the oscillation speed and the moving speed on the basis of the allowable setting range when it is determined by the determining mans that the relationship between the oscillation speed and the moving speed is inappropriate.
(21) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form using a blade, includes
oscillating means for laterally oscillating the blade;
moving means for moving the blade in an incising direction;
setting means for variably setting two parameters which respectively correspond to an oscillation speed of the blade defined by the oscillating means and a moving speed of the blade defined by the moving means;
storing means for storing a relative allowable setting range of the oscillation speed and the moving speed;
limiting means for limiting the allowable setting range of one of the parameters on the basis of both the allowable setting range stored in the storing means and the other of the parameters set by the setting means; and
controlling means for controlling the oscillating means and the moving means on the basis of the parameters set by the setting means.
(22) The corneal surgical apparatus according to (21), wherein the limiting means determines the allowable setting range of one of the parameters based on the other of the parameters thus set, and displays the thus determined allowable setting range.
(23) The corneal surgical apparatus according to (21), wherein the limiting means determines the allowable setting range of one of the parameters based on the other of the parameters thus set, and permits the setting means to set the one of the parameters within the thus determined allowable setting range.
(24) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form using a blade, comprising:
oscillating means for laterally oscillating the blade;
moving means for moving the blade in an incising direction;
first setting means for variably setting one of two parameters which respectively correspond to an oscillation speed of the blade defined by the oscillating means and a moving speed of the blade defined by the moving means;
storing means for storing an optimum combination of the oscillation speed and the moving speed;
second setting means for setting the other of the parameters on the basis of both and the combination stored in the storing means and the one of the parameters set by the first setting means; and
controlling means for controlling the oscillating means and the moving means on the basis of the parameters set by the first setting means and the second setting means.
(25) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form, includes:
a main body;
a blade movable with respect to the main body; first and second independent motors located within the main body;
a feed screw associated with the first motor;
an attaching member threadingly engaged with the feed screw;
a connecting member connecting the attaching member to the blade; and
a rotating shaft associating the second motor with the blade.
(26) The corneal surgical apparatus according to (25), wherein the second motor is supported by the main body.
(27) The corneal surgical apparatus according to (26), wherein the rotating shaft is coupled to the second motor through a spline coupling.
(28) The corneal surgical apparatus according to (25), wherein the second motor is supported by the attaching member.
(29) The corneal surgical apparatus according to (25), wherein the feeding screw and the attaching member are located within the main body.
(30) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form using a blade, includes:
a first motor associated with the blade for oscillation of the blade;
a second motors associated with the blade for rectilinear movement of the blade; and
an input unit by which rotational speeds of the first and second motors can be set independently from each other.
(31) A corneal surgical apparatus according to (30), further includes:
a control unit, which determines whether the rotational speeds independently set by the input unit are appropriate.
(32) A corneal surgical apparatus according to (30), further includes:
a memory which stores an allowable relationship between the rotational speeds of the first and second motors; and
a control unit, which retrieves the allowable relationship from the memory when at least one of the rotational speeds is set by the input unit.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 10-125441 (filed on Mar. 31, 1998), Hei. 10-363685 (filed on Dec. 22, 1998) and Hei. 10-363687 (filed on Dec. 22, 1998) which are expressly incorporated herein by reference in their entireties.